physics
posted by Jonathan .
A 9.90g bullet has a speed of 1.33 km/s.
(a) What is its kinetic energy in joules?
(b) What is the bullet's kinetic energy if its speed is halved?
(c) What is the bullet's kinetic energy if its speed is doubled?

(a)
(1/2) M V^2.
Make sure M is in kg and V is in m/s.
(b) (1/4) f what it is in (a)
(c) What do you think? What happens to V^2 if you double V?